Machines for picking a single sheet of material from a stack

ABSTRACT

A machine for picking up one top sheet of material from a stack of sheets. The machine buckles the top sheet leaving a surface near the edges of a second sheet beneath the top sheet exposed. A pair of feet urge against the exposed surface holding the second sheet against the stack while suction is applied to the top sheet to assist in lifting it from the stack.

a 1 "1 l l 1 l 1 1! 1 1 19 1 1% [11 3,0,3 Downing May 7, 1974 [54] MACHINES FOR PICKING A SINGLE 754,204 3/1904 Dexter 271 20 SHEET 0F MATERIAL FROM A STACK FOREIGN PATENTS OR APPLICATIONS lnvemori Thomas Downing, Maifland, 628,696 11/1961 l1aly.....1 271/20 [73] Assignee: Acme Conveyor Company, Inc.,

Sandford, Fla. Primary Examiner-Richard E. Aegerter Assistant Examiner.lames W. Miller [22] l 1972 Attorney, Agent, or Firm-Buell, Blenko & [21] ApplhNo; 244,144 Ziesenheim 52 us. c1. 271/20 57 ABSTRACT 2 32 A machine for picking up one top sheet of material 1 le 0 mm from a stack of sheets. The machine buckles the top sheet leaving a surface near the edges of a second 5 References cued I sheet beneath the top sheet exposed.v A pair of feet UNITED STATES PATENTS Y urge against the exposed surface holding the second 1,460,336 6/1923 Hart 271/20 sheet against the stack while suction is applied to the 2,284,429 5/1942 VlI'OUSfik 1 271/20 top sheet to assist in from the tack 2,l5l,073 3/1939 Belluche 271/20 3,430,949 3/1969 Herdeg et al. 271/26 R 5 Claims, 4 Drawing Figures AY 7 I974 PMHED SHEET 1 BF 2 IOJ l MACHINES FOR PICKTNG A SINGLE SHEET F MATERIAL FROM A STACK The invention relates to a machine for picking one sheet of material from a stack of sheets. i

The machine embodying the invention is used to pick up chipboards one at a time from a stack and put them between each layer of cans on a pallet. There are machines in the prior art which are intended to perform this operation. However, due in part to the varying texture and porosity of the chipboards the existing machines frequently pick up several chipboards instead of one and then drop the extra chipboards between the chipboard stack and the pallet of cans.

The applicant's machine eliminates the problem of picking up more than one chipboard at a time from the stack.

I provide an apparatus for picking up one top sheet of material from a stack of sheets comprising: means buckling the top sheet leaving a surface near the edges of the second sheet underneath exposed; means providing suction against the top sheet to lift it from the stack; and means providing compression against the exposed surfaces near the edges of the second sheet underneath.

I preferably provide a pair of compression feet which are urged against the exposed surfaces of the second Positioned on top of frame 10 is a pneumatic cylinder 50 with a piston 52 coupled to frame 10. Also connected to the frame 10 are a pair of guide rods 54 and 56 having guide rod mounting blocks 58 and 60. Connected to the cylinder 50 is conduit piping 62 for the pneumatic line cylinder rod retraction and piping 64 for the pneumatic cylinder extension which are coupled to a suitable supply of air pressure.

FIG. 4 shows a top plan view of the frame 10 which is an H-frame formed by members 66, 68 and center member 70. The frame 10 shows a corresponding pair of suction cups 42 and 44; tension spring 28 and turnbuckle 30'; buckling feet 20' and 22' suspended from legs 12' and 14; and compression feet 32' and sheet underneath the top sheet, a pair of buckling feet pivotally suspended on legs which are pivotally mounted to a frame which is urged against the stack by a pneumatic piston and cylinder arrangement causing the buckling feet to move together and buckle the top sheet which is then lifted by suction cups suspended from the frame which is then raised.

Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof proceeds.

'In the accompanying drawings, I have shown a pres ent preferred embodiment of the invention in which:

FIG. I is a side elevational view showing the machine resting on the stack of sheets;

FIG. 2 is a side elevational view showing the machine as shown in FIG. l where the buckling feet are pressed against the top sheet buckling the top sheet and the suction vacuum cup is in place;

FIG. 3 is a side elevational view identical with FIGS. 3

1 and 2 showing the third sequence of operation with the vacuum suction cups lifting the buckled sheet with the compression feet urging against the remaining sheets in the stack holding them in place; and

FIG. 4 is a top plan view of the structure shown in FIGS. l-3.

FIGS. 1 through 3 show the identical machine in its three sequences of operations referred to above in the description of the figures. A frame 10 supports a pair of legs 12 and '14 which are pivotally mounted at pivot points 16 and 18 respectively and carry buckling feet 20 and 22 which are pivotally mounted at 24 and 26 on legs 12 and 14 respectively. The opposite end of legs 12 and 14 are connected by spring 28 under tension which is adjustable by turnbuckle 30. Mounted to the outside of the frame 10 are a pair of compression feet 32 and 34 which are-urged against the stack of sheets 36 by springs 38 and 40. Positioned between the compression feet 32 and 34 and the buckling feet 20 and 22 are suction cups 42 and 44 which are connected to a suitable vacuum pump not shown through the piping 46 and 48.

The operation is as follows: on command, through suitable circuitry not shown, the pneumatic cylinder 50 extends the piston 52 urging the H-frame 10 against the stack of chipboards 36. The buckling feet 20 and 22 come in contact with the top chipboard 72 causing the buckling feet 20 and 22 to move toward each other thereby buckling the top sheet 72 at its center portion away from the stack. The suction cups 42 and 44 (FIG. 2) are urged against the top chipboard 72 which has been buckled. At this time, there is an exposed surface 74 and 76 of the second sheet beneath the top sheet 72 to which compression feet 32 and 34 urge the second sheet against the stack. The compression feet are further under compression by compression springs 38 and 40. When the suction cups 42 and 44 make contact with the top chipboard the downward switch sensing means 45 comes in contact with the top chipboard and the downward travel of the frame 10 by the pneumatic cylinder 50 and piston 52 is stopped through suitable circuitry not shown. When a vacuum switch not shown then indicates that a vacuum has been achieved at suction cups 42 and 44, the piston 52 begins to raise the frame 10 as shown in FIG. 3. As the frame 10 is raised, tension spring 28 connecting the legs 12 and 14 force the 'feet downward reversing the buckle of the chipboard 72 as shown in FIG. 3. When the unit is raised, compression feet 32 and 34 exert pressure on the exposed areas 74 and 76 of the second sheet beneath the top sheet 72 urging the second sheet against the stack thereby preventing pick-up of more than one chipboard in the event that a vacuum has been pulled through the top chipboard and pulls more than one chipboard at a time.

I claim: 1. Apparatus for picking up in its entirety one top sheet of material from a stack of sheets comprising:

a. a frame carrier; b. a frame depending from said carrier and movable vertically with respect thereto; c. at least one pair of opposed-buckling feet depending from and pivoted on said frame for contacting the top sheet of said stack of sheets; d. means on the frame suspending said buckling feet from the frame at an angle off the vertical so that when the frame is moved toward the stack the opposed feet in contact with the top sheet move toward each other under the action of the frame to buckle the whole sheet between said opposed feet substantially along its center line; e. means on the frame carrier moving the frame vertically with respect thereto toward and away from the stack of sheets;

'of compression feet suspended from the frame so that a buckling foot and a compression foot appear on pposite members of the frame.

3. Apparatus as claimed in claim 1 wherein the means providing suction comprises at least one pair of spaced apart suction cups each mounted on the frame between the buckling feet and the compression foot and coupled to means providing a vacuum to thesuction cups.

4. Apparatus as claimed in claim 1 wherein said buckling feet are mounted on legs privoted intermediate their ends on said frame and normally held at an angle downwardly from the frame and at an angle toward each other so that lowering of the frame with the buckling feet in contact with a sheet causes the feet to move toward each other under the force of the frame and tension means acting on the legs opposite the buckling feet urging them to return to their normally held position.

5. Apparatus as claimed in claim 1 having limit switch means to stop the movement of the frame toward the sheet stack when the suction means has engaged the top sheet. 

1. Apparatus for picking up in its entirety one top sheet of material from a stack of sheets comprising: a. a frame carrier; b. a frame depending from said carrier and movable vertically with respect thereto; c. at least one pair of opposed buckling feet depending from and pivoted on said frame for contacting the top sheet of said stack of sheets; d. means on the frame suspending said buckling feet from the frame at an angle off the vertical so that when the frame is moved toward the stack the opposed feet in contact with the top sheet move toward each other under the action of the frame to buckle the whole sheet between said opposed feet substantially along its center line; e. means on the frame carrier moving the frame vertically with respect thereto toward and away from the stack of sheets; f. means on the frame providing suction against the top sheet to lift the top sheet from the stack while buckled; g. means on the frame providing compression against the two exposed edge surfaces of a second sheet on each side of the buckled sheet underneath the top sheet while the top sheet is buckled and to hold said second sheet against pick-up by the means providing suction.
 2. Apparatus as claimed in claim 1 wherein the frame is H-shapEd with the pair of buckling feet and the pair of compression feet suspended from the frame so that a buckling foot and a compression foot appear on opposite members of the frame.
 3. Apparatus as claimed in claim 1 wherein the means providing suction comprises at least one pair of spaced apart suction cups each mounted on the frame between the buckling feet and the compression foot and coupled to means providing a vacuum to the suction cups.
 4. Apparatus as claimed in claim 1 wherein said buckling feet are mounted on legs privoted intermediate their ends on said frame and normally held at an angle downwardly from the frame and at an angle toward each other so that lowering of the frame with the buckling feet in contact with a sheet causes the feet to move toward each other under the force of the frame and tension means acting on the legs opposite the buckling feet urging them to return to their normally held position.
 5. Apparatus as claimed in claim 1 having limit switch means to stop the movement of the frame toward the sheet stack when the suction means has engaged the top sheet. 